Camera Optical Lens

ABSTRACT

The present disclosure discloses a camera optical lens. The camera optical lens includes, in an order from an object side to an image side, a first lens, an aperture, a second lens, a third lens, a fourth lens, and a fifth lens. The camera optical lens further satisfies specific conditions.

FIELD OF THE PRESENT DISCLOSURE

The present disclosure relates to optical lens, in particular to acamera optical lens suitable for handheld devices such as smart phonesand digital cameras and imaging devices.

DESCRIPTION OF RELATED ART

With the emergence of smart phones in recent years, the demand forminiature camera lens is increasing day by day, but the photosensitivedevices of general camera lens are no other than Charge Coupled Device(CCD) or Complementary metal-Oxide Semiconductor Sensor (CMOS sensor),and as the progress of the semiconductor manufacturing technology makesthe pixel size of the photosensitive devices shrink, coupled with thecurrent development trend of electronic products being that theirfunctions should be better and their shape should be thin and small,miniature camera lens with good imaging quality therefor has become amainstream in the market. In order to obtain better imaging quality, thelens that is traditionally equipped in mobile phone cameras adopts athree-piece or four-piece lens structure. And, with the development oftechnology and the increase of the diverse demands of users, and underthis circumstances that the pixel area of photosensitive devices isshrinking steadily and the requirement of the system for the imagingquality is improving constantly, the five-piece, six-piece andseven-piece lens structure gradually appear in lens design. There is anurgent need for ultra-thin wide-angle camera lenses which have goodoptical characteristics and the chromatic aberration of which is fullycorrected.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the exemplary embodiments can be better understood withreference to the following drawings. The components in the drawing arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present disclosure.

FIG. 1 is a schematic diagram of a camera optical lens in accordancewith a first embodiment of the present invention;

FIG. 2 shows the longitudinal aberration of the camera optical lensshown in FIG. 1;

FIG. 3 shows the lateral color of the camera optical lens shown in FIG.1;

FIG. 4 presents a schematic diagram of the field curvature anddistortion of the camera optical lens shown in FIG. 1;

FIG. 5 is a schematic diagram of a camera optical lens in accordancewith a second embodiment of the present invention;

FIG. 6 presents the longitudinal aberration of the camera optical lensshown in FIG. 5;

FIG. 7 presents the lateral color of the camera optical lens shown inFIG. 5;

FIG. 8 presents the field curvature and distortion of the camera opticallens shown in FIG. 5;

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure will hereinafter be described in detail withreference to several exemplary embodiments. To make the technicalproblems to be solved, technical solutions and beneficial effects of thepresent disclosure more apparent, the present disclosure is described infurther detail together with the figure and the embodiments. It shouldbe understood the specific embodiments described hereby is only toexplain the disclosure, not intended to limit the disclosure.

Embodiment 1

As referring to FIG. 1, the present invention provides a camera opticallens 10. FIG. 1 shows the camera optical lens 10 of embodiment 1 of thepresent invention, the camera optical lens 10 comprises 5 lenses.Specifically, from the object side to the image side, the camera opticallens 10 comprises in sequence: a first lens L1, an aperture St, a secondlens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. Opticalelement like optical filter GF can be arranged between the fifth lens L5and the image surface Si.

In this embodiment, the first lens L1 has a positive refractive powerwith a convex object side surface relative to the proximal axis and aconcave image side surface relative to the proximal axis which caneffectively reduce length of the system, the second lens L2 has apositive refractive power with a concave object side surface relative tothe proximal axis and a convex image side surface relative to theproximal axis which can effectively reduce length of the system, theaperture St is arranged between the first lens L1 and the second lensL2. The third lens L3 has a negative refractive power with a concaveobject side surface relative to the proximal axis and a concave imageside surface relative to the proximal axis. The fourth lens L4 has apositive refractive power with a concave object side surface relative tothe proximal axis and a convex image side surface relative to theproximal axis, the fifth lens L5 has a negative refractive power with aconvex object side surface relative to the proximal axis and a concaveimage side surface relative to the proximal axis.

Here, the focal length of the whole camera optical lens 10 is defined asf, the focal length of the first lens L1 is defined as f1, the focallength of the second lens L2 is defined as f2, the refractive power ofthe second lens L2 is defined as n2, the abbe number of the second lensL2 is defined as ν2, the thickness on-axis of the second lens L2 isdefined as d3, the distance on-axis from the image side surface of thefirst lens L1 to the object side surface of the second lens L2 isdefined as d2, the distance on-axis from the image side surface of thesecond lens L2 to the object side surface of the third lens L3 isdefined as d4, the total optical length of the camera optical lens isdefined as TTL, the curvature radius of the object side surface of thesecond lens L2 is defined as R3, the curvature radius of the image sidesurface of the second lens L2 is defined as R4. The following conditionshould satisfied: 1<f1/f<1.55; 1<f2/f<1.55; 1<(R3+R4)/(R3−R4)<4;1.75<n2<2.2, 35<ν2<45; 0.05<d3/TTL<0.1, 0.05<d2/TTL<0.1;0.005<d4/TTL<0.01.

When the focal length of the camera optical lens 10 of the presentinvention, the focal length of related lens, the curvature radius of therelated lens, the refractive power of the related lens, the abbe numberof the related lens, the thickness on-axis of the related lens, thespacing of the related lens, and the total optical length satisfy theabove conditions, the camera optical lens 10 has the advantage of highperformance and satisfies the wide-angle of the camera optical lens.

In this embodiment, the focal length of the whole camera optical lens isdefined as f, the focal length of the first lens L1 is defined as f1,the focal length of the second lens L2 is defined as f2, the focallength of the third lens L3 is defined as f3, the focal length of thefourth lens L4 is defined as f4, and the focal length of the fifth lensL5 is defined as f5. Here the following condition should satisfied:1<f1/f<1.5; 1<f2/f<1.5; −3<f3/f<−1; 0.5<f4/f<2; −2<f5/f<−0.5. The unitof distance, radius and center thickness is mm. With such design, thetotal optical length TTL of the whole camera optical lens 10 can be madeas short as possible, thus the miniaturization characteristics can bemaintained.

In this embodiment, the first lens L1 is made of plastic material, thesecond lens L2 is made of glass material, the third lens L3 is made ofplastic material, the fourth lens L4 is made of plastic material, thefifth lens L5 is made of plastic material, This design effectivelyimproves the optical performance of the camera optical lens 10, andprovides the camera lens 10 with better reliability under differentconditions of temperature and humidity.

In this embodiment, the refractive power of the first lens L1 is todefined as n 1, the refractive power of the second lens L2 is defined asn2, the refractive power of the third lens L3 is defined as n3, therefractive power of the fourth lens L4 is defined as n4, the refractivepower of the fifth lens L5 is defined as n5, the following conditionshall be satisfied, 1.5<n1<1.65; 1.5<n3<1.7; 1.5<n4<1.7; 1.5<n5<1.7.Such design enables the lenses made from different optical materials tomatch each other better, and further enables the camera lens 10 toperform better imaging quality.

In this embodiment, the abbe number of the first lens L1 is defined asν1, the abbe number of the third lens L3 is defined as ν3, the abbenumber of the fourth lens L4 is defined as ν4, the abbe number of thefifth lens L5 is defined as ν5. Here the following condition shouldsatisfied: 40<ν1<65; 15<ν3<30; 15<ν4<30; 15<ν5<30. The satisfiedcondition is beneficial to correction of aberration. This design cansuppress optical color difference when the optical lens 10 works.

Configurations of refractive index and abbe number of the lensesmentioned above can be combined and applied for designing the cameraoptical lens 10. the third lens L3, the fourth lens L4 and the fifthlens L5 made from materials with high dispersion can effectively reducecolor difference of the system and greatly improve the imaging qualityof the camera optical lens 10. Besides, the second lens L2 uses opticalmaterials with high refractive index which can effectively achievewide-angle of the system.

Preferably, inflexion points and/or arrest points can also be arrangedon the object side surface and/or image side surface of the lens, sothat the demand for high quality imaging can be satisfied, thedescription below can be referred for specific implementable scheme.

The design information of the camera optical lens 10 in the firstembodiment of the present invention is shown in the tables 1 and 2.

TABLE 1 focal length (mm) f 3.220344252 f1 4.840661701 f2 3.657980784 f3−4.722770736 f4 2.724712528 f5 −2.597988916 f12 2.398393238

Where:

In which, the meaning of the various symbols is as follows.

f: the focal length of the camera optical lens 10;

f1: the focal length of the first lens;

f2: the focal length of the second lens;

f3: the focal length of the third lens;

f4: the focal length of the fourth lens;

f5: the focal length of the fifth lens.

f12: the combined focal length of the first lens L1 and the second lensL2.

TABLE 2 Curvature radius Thickness/Distance Refractive power Abbe number(R) (mm) (d) (mm) (nd) (νd) St St ∞ d0= −0.255 L1 R1 1.540 d1= 0.401 nd11.5445 ν1 55.99 R2 3.386 d2= 0.375 L2 R3 −8.225 d3= 0.403 nd2 1.8059 ν240.95 R4 −2.206 d4= 0.030 L3 R5 −6.225 d5= 0.270 nd3 1.6713 ν3 19.24 R66.398 d6= 0.569 L4 R7 −2.456 d7= 0.746 nd4 1.6150 ν4 25.92 R8 −1.104 d8=0.245 L5 R9 2.120 d9= 0.392 nd5 1.6448 ν5 22.44 R10 0.863 d10= 0.300Glass R11 ∞ d11= 0.110 ndg 1.5160 νg 64.16 R12 ∞ d12= 0.656

In which, R1 and R2 represent respectively the object side surface andimage side surface of the first lens L1, R3 and R4 representrespectively the object side surface and image side surface of thesecond lens L2, R5 and R6 represent respectively the object side surfaceand image side surface of the third lens L3, R7 and R8 representrespectively the object side surface and image side surface of thefourth lens L4, R9 and R10 represent respectively the object sidesurface and image side surface of the fifth lens L5, R11 and R12represent respectively the object side surface and image side surface ofthe optical filter GF. Other, the meaning of the various symbols is asfollows.

d0: The distance on-axis from aperture St to the object side surface ofthe first lens L1;

d1: The thickness on-axis of the first lens L1;

d2: The distance on-axis from the image side surface of the first lensL1 to the object side surface of the second lens L2;

d3: The thickness on-axis of the second lens L2;

d4: The distance on-axis from the image side surface of the second lensL2 to the object side surface of the third lens L3;

d5: The thickness on-axis of the third lens L3;

d6: The distance on-axis from the image side surface of the third lensL3 to the object side surface of the fourth lens L4;

d7: The thickness on-axis of the fourth lens L4;

d8: The distance on-axis from the image side surface of the fourth lensL4 to the object side surface of the fifth lens L5;

d9: The thickness on-axis of the fifth lens L5;

d10: The distance on-axis from the image side surface of the fifth lensL5 to the object side surface of the optical filter GF;

d11: The thickness on-axis of the optical filter GF;

d12: The distance on-axis from the image side surface to the imagesurface of the optical filter GF;

nd1: The refractive power of the first lens L1;

nd2: The refractive power of the second lens L2;

nd3: The refractive power of the third lens L3;

nd4: The refractive power of the fourth lens L4;

nd5: The refractive power of the fifth lens L5;

ndg: The refractive power of the optical filter GF;

ν1: The abbe number of the first lens L1;

ν2: The abbe number of the second lens L2;

ν3: The abbe number of the third lens L3;

ν4: The abbe number of the fourth lens L4;

ν5: The abbe number of the fifth lens L5;

vg: The abbe number of the optical filter GF.

Table 3 shows the aspherical surface data of the camera optical lens 10in the embodiment 1 of the present invention.

TABLE 3 Conic Index Aspherical Surface Index k A4 A6 A8 A10 A12 R1 9.9484E−01 −5.0925E−02 1.6936E−01 −1.2939E+00 5.0759E+00 −1.3103E+01 R2−4.9678E+00  1.6007E−02 −2.3523E−01   1.9422E+00 −1.0971E+01  3.6293E+01 R3  4.6353E+00 −6.1302E−02 4.9132E−02 −1.2504E+00 6.7277E+00−2.1944E+01 R4 −6.8882E+00 −2.7997E−01 7.0602E−01 −2.3732E+00 4.4327E+00−3.2055E+00 R5 −4.2717E+01 −4.6267E−01 1.2516E+00 −4.7971E+00 1.4121E+01−3.1191E+01 R6  2.0507E+01 −2.2423E−01 2.3486E−01 −3.2297E−01 1.5343E−01 2.7605E−01 R7 −2.7812E+00 −5.4401E−02 −1.5043E−01   5.9712E−01−1.6503E+00   2.7845E+00 R8 −9.3003E−01 −8.4513E−03 2.3256E−01−6.4427E−01 9.7819E−01 −9.3190E−01 R9 −4.2583E+01 −1.9195E−01 1.3850E−01−7.5809E−02 3.2450E−02 −9.9894E−03 R10 −5.5966E+00 −1.2564E−018.0795E−02 −3.9450E−02 1.3421E−02 −3.1349E−03 Aspherical Surface IndexA14 A16 A18 A20 R1 2.1287E+01 −2.1207E+01 1.1658E+01 −2.6989E+00 R2−7.4063E+01   9.0347E+01 −6.0072E+01   1.6723E+01 R3 4.2269E+01−4.6087E+01 2.4180E+01 −3.3537E+00 R4 −5.5254E+00   1.5792E+01−1.4954E+01   5.2807E+00 R5 4.7998E+01 −4.8400E+01 2.8860E+01−7.7203E+00 R6 −6.1444E−01   5.2621E−01 −2.0159E−01   2.7261E−02 R7−2.8372E+00   1.7015E+00 −5.4742E−01   7.2473E−02 R8 5.6659E−01−2.0825E−01 4.1705E−02 −3.4840E−03 R9 2.0819E−03 −2.7676E−04 2.1138E−05−7.0595E−07 R10 4.9089E−04 −4.9142E−05 2.8425E−06 −7.2311E−08

Table 4 and table 5 show the inflexion points and the arrest pointdesign data of the camera optical lens 10 lens in embodiment 1 of thepresent invention. In which, R1 and R2 represent respectively the objectside surface and image side surface of the first lens L1, R3 and R4represent respectively the object side surface and image side surface ofthe second lens L2, R5 and R6 represent respectively the object sidesurface and image side surface of the third lens L3, R7 and R8 representrespectively the object side surface and image side surface of thefourth lens L4, R9 and R10 represent respectively the object sidesurface and image side surface of the fifth lens L5. The data in thecolumn named “inflexion point position” are the vertical distances fromthe inflexion points arranged on each lens surface to the optic axis ofthe camera optical lens 10. The data in the column named “arrest pointposition” are the vertical distances from the arrest points arranged oneach lens surface to the optic axis of the camera optical lens 10.

TABLE 4 Inflexion point Inflexion point Inflexion point Inflexion pointnumber position 1 position 2 position 3 R1 1 0.805 R2 1 0.595 R3 0 R4 0R5 0 R6 2 0.275 0.995 R7 1 1.095 R8 2 1.115 1.525 R9 3 0.315 1.585 2.255R10 1 0.525

TABLE 5 Arrest point number Arrest point position 1 R1 0 R2 0 R3 0 R4 0R5 0 R6 1 0.495 R7 0 R8 0 R9 1 0.645 R10 1 1.475

FIG. 2 and FIG. 3 show the longitudinal aberration and lateral colorschematic diagrams after light with a wavelength of 486 nm, 588 nm and656 nm passes the camera optical lens 10 in the first embodiment. FIG. 4shows the field curvature and distortion schematic diagrams after lightwith a wavelength of 588 nm passes the camera optical lens 10 in thefirst embodiment.

Table 6 shows the various values of the embodiments and the valuescorresponding with the parameters which are already specified in theconditions.

As shown in Table 6, the first embodiment satisfies the variousconditions.

TABLE 6 Embodiment 1 1 < f1/f < 1.55 1.503 1 < f2/f < 1.55 1.136 1 <(R3 + R4)/(R3 − R4) < 4 1.733 1.75 < n2 < 2.2 1.806 35 < v2 < 45 40.9480.05 < d3/TTL < 0.1 0.08963145 0.05 < d2/TTL < 0.1 0.083428608 0.005 <d4/TTL < 0.01 0.006667052

In this embodiment, the pupil entering diameter of the camera opticallens is 1.642 mm, the full vision field image height is 3.24 mm, thevision field angle in the diagonal direction is 88.52°.

Embodiment 2

Embodiment 2 is basically the same as embodiment 1, the meaning of itssymbols is the same as that of embodiment 1, in the following, only thedifferences are described.

Table 7 and table 8 show the design data of the camera optical lens inembodiment 2 of the present invention.

TABLE 7 focal length (mm) f 3.202580008 f1 3.847055533 f2 4.815284349 f3−4.912654699 f4 2.145756042 f5 −1.964328028 f12 2.451255474

TABLE 8 Curvature radius Thickness/Distance Refractive power Abbe number(R) (mm) (d) (mm) (nd) (νd) St St ∞ d0= −0.255 L1 R1 1.416 d1= 0.474 nd11.5445 ν1 55.99 R2 3.851 d2= 0.319 L2 R3 −6.473 d3= 0.385 nd2 1.8059 ν240.95 R4 −2.490 d4= 0.030 L3 R5 −7.590 d5= 0.347 nd3 1.6713 ν3 19.24 R65.940 d6= 0.387 L4 R7 −2.711 d7= 0.843 nd4 1.6150 ν4 25.92 R8 −0.993 d8=0.175 L5 R9 5.845 d9= 0.475 nd5 1.6448 ν5 22.44 R10 1.008 d10= 0.300Glass R11 ∞ d11= 0.110 ndg 1.5160 νg 64.16 R12 ∞ d12= 0.575

Table 9 shows the aspherical surface data of each lens of the cameraoptical lens 20 in embodiment 2 of the present invention.

TABLE 9 Conic Index Aspherical Surface Index k A4 A6 A8 A10 A12 R1 8.8889E−01 −5.9892E−02 2.9371E−01 −2.1176E+00 8.8338E+00 −2.3943E+01 R2−2.4422E+00  4.2105E−02 −6.1209E−01   5.4330E+00 −3.0583E+01  1.0531E+02 R3  4.6276E+00 −1.7976E−02 −8.1042E−01   8.8202E+00−6.3644E+01   2.8572E+02 R4 −4.7858E+00 −4.2000E−01 1.9082E+00−9.3322E+00 3.1749E+01 −7.2106E+01 R5 −1.6033E+01 −6.4481E−01 2.5794E+00−1.1863E+01 4.0131E+01 −9.4081E+01 R6  2.1984E+01 −2.1638E−01 3.7431E−01−9.1403E−01 1.9978E+00 −3.3213E+00 R7 −5.4399E+00 −8.9617E−02−7.4830E−02   1.9582E−02 3.4465E−01 −5.3105E−01 R8 −9.8846E−01 1.0641E−01 −2.1736E−01   3.1294E−01 −3.2048E−01   2.1388E−01 R9−9.0000E+01 −3.0030E−01 2.4460E−01 −1.1675E−01 3.7469E−02 −8.4474E−03R10 −6.2657E+00 −1.5283E−01 1.0150E−01 −4.8294E−02 1.5935E−02−3.6285E−03 Aspherical Surface Index A14 A16 A18 A20 R1 4.0679E+01−4.2039E+01 2.3975E+01 −5.8222E+00 R2 −2.2633E+02   2.9424E+02−2.1114E+02   6.4125E+01 R3 −8.0700E+02   1.3893E+03 −1.3312E+03  5.4466E+02 R4 9.7521E+01 −6.3013E+01 1.9197E+00  1.2769E+01 R51.3857E+02 −1.1473E+02 4.2083E+01 −2.0141E+00 R6 3.7312E+00 −2.5803E+009.8205E−01 −1.5711E−01 R7 3.2939E−01 −4.9890E−02 −3.5592E−02  1.2089E−02 R8 −6.2232E−02  −4.4589E−03 6.2151E−03 −9.3865E−04 R91.3596E−03 −1.5182E−04 1.0565E−05 −3.4156E−07 R10 5.5635E−04 −5.4856E−053.1551E−06 −8.0753E−08

Table 10 and table 11 show the inflexion points and the arrest pointdesign data of the camera optical lens 20 lens in embodiment 2 of thepresent invention. The data in the column named “inflexion pointposition” are the vertical distances from the inflexion points arrangedon each lens surface to the optic axis of the camera optical lens 20.The data in the column named “arrest point position” are the verticaldistances from the arrest points arranged on each lens surface to theoptic axis of the camera optical lens 20.

TABLE 10 Inflexion point Inflexion point Inflexion point Inflexion pointnumber position 1 position 2 position 3 R1 1 0.855 R2 1 0.605 R3 0 R4 10.815 R5 0 R6 2 0.325 0.925 R7 2 0.955 1.105 R8 2 1.035 1.415 R9 3 0.2151.315 2.315 R10 3 0.495 2.515 2.635

TABLE 11 Arrest point Arrest point Arrest point number position 1position 2 R1 0 R2 0 R3 0 R4 0 R5 0 R6 2 0.635 1.075 R7 0 R8 0 R9 10.385 R10 1 1.325

FIG. 6 and FIG. 7 show the longitudinal aberration and lateral colorschematic diagrams after light with a wavelength of 486 nm, 588 nm and656 nm passes the camera optical lens 20 in the second embodiment. FIG.8 shows the field curvature and distortion schematic diagrams afterlight with a wavelength of 588 nm passes the camera optical lens 20 inthe second embodiment.

As shown in Table 12, the second embodiment satisfies the variousconditions.

TABLE 12 Embodiment 2 1 < f1/f < 1.55 1.201 1 < f2/f < 1.55 1.504 1 <(R3 + R4)/(R3 − R4) < 4 2.251 1.75 < n2 < 2.2 1.806 35 < v2 < 45 40.9480.05 < d3/TTL < 0.1 0.08698722 0.05 < d2/TTL < 0.1 0.071991358 0.005 <d4/TTL < 0.01 0.006778987

In this embodiment, the pupil entering diameter of the camera opticallens is 1.651 mm, the full vision field image height is 3.24 mm, thevision field angle in the diagonal direction is 88.52°.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present exemplary embodiments havebeen set forth in the foregoing description, together with details ofthe structures and functions of the embodiments, the disclosure isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts within the principlesof the invention to the full extent indicated by the broad generalmeaning of the terms where the appended claims are expressed.

What is claimed is:
 1. A camera optical lens comprising, from an objectside to an image side in sequence: a first lens having a positiverefractive power, an aperture, a second lens having a positiverefractive power, a third lens having a negative refractive power, afourth lens having a positive refractive power, a fifth lens having anegative refractive power; wherein the camera optical lens furthersatisfies the following conditions:1<f1/f<1.55;1<f2/f<1.55;1<(R3+R4)/(R3−R4)<4;1.75<n2<2.2;35<ν2<45;0.05<d3/TTL<0.1;0.05<d2/TTL<0.1;0.005<d4/TTL<0.01. where f: the focal length of the camera optical lens;f1: the focal length of the first lens; f2: the focal length of thesecond lens; R3: the curvature radius of object side surface of thesecond lens; R4: the curvature radius of image side surface of thesecond lens; n2: the refractive power of the second lens; ν2: the abbenumber of the second lens L2; d3: the thickness on-axis of the secondlens L2; d2: the distance on-axis from the image side surface of thefirst lens L1 to the object side surface of the second lens L2; d4: thedistance on-axis from the image side surface of the second lens L2 tothe object side surface of the third lens L3; TTL: the total opticallength of the camera optical lens.
 2. The camera optical lens asdescribed in claim 1 further satisfying the following conditions:1<f1/f<1.5;1<f2/f<1.5;−3<f3/f<−1;0.5<f4/f<2;−2<f5/f<−0.5; where f3: the focal length of the third lens; f4: thefocal length of the fourth lens; f5: the focal length of the fifth lens;3. The camera optical lens as described in claim 1, further satisfyingthe following conditions:1.5<n1<1.65;1.5<n3<1.7;1.5<n4<1.7;1.5<n5<1.7; where n1: the refractive power of the first lens; n3: therefractive power of the third lens; n4: the refractive power of thefourth lens; n5: the refractive power of the fifth lens.
 4. The cameraoptical lens as described in claim 1 further satisfying the followingconditions:40<ν1<65;15<ν3<30;15<ν4<30;15<ν5<30; where ν1: The abbe number of the first lens; ν3: The abbenumber of the third lens; ν4: The abbe number of the fourth lens; ν5:The abbe number of the fifth lens.